As part of my work on workarounds for region crossing problems, I need for a vehicle script to be able to talk to seated avatars during the semi-broken condition of a half-unsit, where a region crossing has failed. I want to tell the avatar to teleport itself back to the vehicle. This works when vehicle and avatar extension can communicate. The communication is a problem:
llShout will work up to 100m across region boundaries, but sometimes the avatar is more than 100m from the vehicle. Seldom if ever more than a few hundred meters, though.
llEmail has a lot of open bugs dated back to 2005. Discussions consider it broken.
llTeleportAgent will work if the avatar is the owner of the vehicle. Otherwise not.
llInstantMessage can't talk to an object.
llRegionSayTo is only useful within a region.
llMessageLinked can't talk to an attachment (and might not work when avatar and vehicle are in different regions, which is what this is all about)
Setting up an external server for HTTP communication is a bit much. This isn't some big coordinated system under one owner.
Have I missed anything?